Document Type

Article

Publication Date

10-31-1991

Department

Chemistry and Biochemistry

School

Mathematics and Natural Sciences

Abstract

The photo-Fries rearrangement has been observed for the aryl cinnamate chromophore in both polyaryl cinnamates and small-molecule models. Laser flash photolysis of solutions of aryl cinnamates and the corresponding polymers leads to phenoxy and cinnamoyl radicals from the cleavage of the CO ester bond. The formation of these radicals has been verified by their independent generation by flash photolysis of phenols (e.g. p-pentyloxyphenol) and aldehydes (e.g. p-methoxycinnamaldehyde). The effects of triplet sensitizers and quenchers on the formation of these transient intermediates and on the formation of the photo-Fries rearrangement products are reported. It is concluded that these products arise from either the aryl cinnamate singlet state or a short-lived upper triplet state.